//视觉切换
function viewChange(){
    let logitude = param.logitude
    let latitude = param.latitude
    let altitude = param.altitude
    let heading = param.heading
    let pitch = param.pitch
    let roll = param.roll
    let duration = param.duration

    viewer.camera.flyTo({
        duration:duration,
        destination:Cesium.Cartesian3.fromDegrees(logitude,latitude,altitude),
        orientation:{
            heading:heading,
            pitch:pitch,
            roll:roll
        }
    })
}